linux-kernel - [PATCH 2/6] KVM: arm64: pkvm: Disable GICv2 support

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Date:   Wed,  8 Dec 2021 15:22:55 +0000
From:   Quentin Perret <qperret@...gle.com>
To:     Marc Zyngier <maz@...nel.org>, James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        linux-kernel@...r.kernel.org, kernel-team@...roid.com,
        qperret@...gle.com
Subject: [PATCH 2/6] KVM: arm64: pkvm: Disable GICv2 support

GICv2 requires having device mappings in guests and the hypervisor,
which is incompatible with the current pKVM EL2 page ownership model
which only covers memory. While it would be desirable to support pKVM
with GICv2, this will require a lot more work, so let's make the
current assumption clear until then.

Co-developed-by: Marc Zyngier <maz@...nel.org>
Signed-off-by: Marc Zyngier <maz@...nel.org>
Signed-off-by: Quentin Perret <qperret@...gle.com>
---
 arch/arm64/kvm/vgic/vgic-v2.c | 5 +++++
 arch/arm64/kvm/vgic/vgic-v3.c | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/vgic/vgic-v2.c b/arch/arm64/kvm/vgic/vgic-v2.c
index 95a18cec14a3..8e337a0d7817 100644
--- a/arch/arm64/kvm/vgic/vgic-v2.c
+++ b/arch/arm64/kvm/vgic/vgic-v2.c
@@ -345,6 +345,11 @@ int vgic_v2_probe(const struct gic_kvm_info *info)
 	int ret;
 	u32 vtr;
 
+	if (is_protected_kvm_enabled()) {
+		kvm_err("GICv2 not supported in protected mode\n");
+		return -ENXIO;
+	}
+
 	if (!info->vctrl.start) {
 		kvm_err("GICH not present in the firmware table\n");
 		return -ENXIO;
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index 04f62c4b07fb..debad4e6e6c9 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c
@@ -651,7 +651,7 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
 	} else if (!PAGE_ALIGNED(info->vcpu.start)) {
 		pr_warn("GICV physical address 0x%llx not page aligned\n",
 			(unsigned long long)info->vcpu.start);
-	} else {
+	} else if (kvm_get_mode() != KVM_MODE_PROTECTED) {
 		kvm_vgic_global_state.vcpu_base = info->vcpu.start;
 		kvm_vgic_global_state.can_emulate_gicv2 = true;
 		ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
-- 
2.34.1.400.ga245620fadb-goog